Method of making a dynamoelectric machine insulator

ABSTRACT

Electrical insulators are formed from insulative strip material by providing a substantially continuous ultrasonically welded seam. In one embodiment a tubular insulator for covering stator winding connections is formed by continuously moving the strip and a strip of dissimilar material about a cylindrical former having its axis in generally the same direction as the direction of elongation and motion of the strips to thereby form a multiple layer sleeve with a seam being ultrasonically formed to include the two edges of the strip of polyester material. In a second embodiment two or more parallel elongated narrow flat strips are moved in their direction of elongation with a plurality of flat sheets of polyester material being ultrasonically bonded thereto along a substantially continuous seam on the individual sheets with the individual sheets occurring at uniform intervals along the strips to thereby form a ladder-like strip of insulators. In both embodiments the strip is periodically severed after bonding to form individual insulators. In the case of the second embodiment this severing occurs along a line substantially perpendicular to the direction of elongation of the strips, and in a manner to separate the flat sheets into two approximately equal pieces to thereby form phase insulators for stator windings. Substantially continuous ultrasonically formed seams are achieved with surprisingly little tool wear. Tools are case hardened at least along the surface engaging portions or welding tips thereof. Relatively continuous welded seams are achieved by providing ultrasonic vibrations to the tool tip.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of my copending applicationSer. No. 333,786 filed Feb. 20, 1973, and the entire disclosure of saidcopending application is incorporated herein by reference thatapplication issued as U.S. Pat. No. 3,880,194 on Apr. 29, 1975.

U.S. Pat. No. 3,748,510, which issued July 24, 1973 from my applicationfiled Oct. 26, 1971, assigned to the assignee of this application is arelated patent, and the entire disclosure of said patent is incorporatedherein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to apparatus and methods for joiningtogether different pieces of materials along a continuous ultrasonicallywelded seam to form electrical insulators; and to a new and improvedinsulator for use in dynamoelectric machine stator assemblies.

The manufacture of dynamoelectric machines has developed into a highlysophisticated industry. In the manufacture of wound stators for suchmachines, coils may be wound on a coil form and then inserted into thestator; or the wire for forming such coils may be directly dispensedinto the stat or slots in a so-called "in-slot" winding process. Ineither approach various insulators are employed in addition to thetypical ground insulation that is immediately adjacent to coilaccommodating surfaces of the core. For example, an exemplary statorslot may have a cuffed stator slot wedge or slot liner, such asillustrated in U.S. Pat. No. 2,935,859, inserted therein before any wireis deposited in that slot, although slot insulation may also take theform of an epoxy or other resinous coating. With the slot liner inplace, a first phase winding may then be inserted in the slot to befollowed by a phase insulating wedge or separator. Next, a secondwinding is inserted in this slot and, lastly, an insulating wedge isinserted in the slot. In this example, where two different phasewindings occupy the same slot, it is also desirable to provideadditional insulation between the end turns of the two different phases.This additional end turn insulation is sometimes called "window"insulation in the art, and an example of such an approach is shown inU.S. Pat. No. 2,701,317, which was assigned to the assignee of thisapplication. There may also occur connections between different polewindings of the stator and connections from such windings to the statorleads. To insulate such connections, there may be provided additionalinsulators often in the form of insulators or sleeves such as thosedisclosed in U.S. Pat. No. 3,219,857 (which is assigned to the assigneeof this application), which fit over the interconnected wires and toeither side of a particular point of connection. Since these interpoleor external lead connections are often soldered, sharp protrusions maybe present, and the tubular insulators should be particularly rugged.Stator insulators have at one time or another been manufactured of paperand also of polyester materials, such as polyethylene terephthalatewhich may be purchased under the trade name "Mylar" polyester. Thepolyester materials have proven to be particularly desirable materialsbecause of their strength, good electrical insulating properties, andcompatibility with lubricants and refrigerants normally encountered inhermetically sealed refrigeration compressor motor parts.

In a hermetically sealed compressor environment, quality of insulationis particularly important since such insulation comes in contact withrefrigerant and lubricants employed in the refrigeration system and anyinsulation failure may result in loss of not only the motor but anentire compressor unit. Any moisture which might be present in theinsulators at the time of assembly could of course lead to system damageif that moisture were to subsequently freeze and block the refrigerantcirculation path. Because of those considerations such insulators arenow almost universally fabricated from synthetic materials, of whichpolyethylene terephthalate or Mylar polyester will be taken as exemplarythroughout the present specification.

While polyethylene terephthalate is particularly suited to the hermeticmotor environment, it can be a difficult material to work with and israther costly. Heating this material in an attempt to bind two pieces ofpolyester sheet material together results in a thermal degradation ofthe material which not only weakens the material but also changes itschemical properties somewhat so that the material may be more prone toabsorb moisture. Also, if it is overly heated refrigerants such as Freonmay later cause a molecular particle to leave the insulator andcontaminate the freon base refrigerant. Attempts have been made to bondtwo sheets of polyethylene terephthalate together by ultrasonic spotwelding techniques. However, such welds are not characterized by greatstrength, and I have found that ultrasonic welding of such material isso detrimental to the ultrasonic welding tips that such tips wouldrapidly wear away and require replacement. Adhesive or solvent bondingof polyester to polyester is expensive, does not result in particularlystrong bonds, and introduces undesirable materials which again may bedetrimental in a refrigerant compressor environment.

Present production techniques of, for example, phase insulators is tocut thee insulator from a flat sheet of material and discard almost asmuch material as is retained for the end turn or phase insulator. Thecost of discarding such a substantial quantity of insulating material isof course substantial.

It is accordingly a general object of the present invention to overcomeone or more of the foregoing problems.

It is another object of the present invention to provide new andimproved electrical insulators from strip insulating material.

A further object of the present invention is to provide a new andimproved method for fabricating connection insulators for interpole andwinding lead connections in dynamoelectric machines.

A still further object of the present invention is to provide a new andimproved and economical phase insulator for dynamoelectric machinestator windings.

Still another object of the present invention is to join polyestermaterials together without degrading the materials.

A yet further object of the present invention is to effect asubstantially continuous polyester material to polyester materialultrasonically welded seam and improved apparatus for use therewith.

It has been recognized in the art that ultrasonic welder tip wear is asubstantial problem, and particularly so in connection with weldingpolyester materials such as polyethylene terephthalate. In fact, theindustry makes use of exotic welder tip materials such as titaniumalloys, in an effort to reduce welder tip wear. Attempts to harden thetip or portion of the machinery which transmits the ultrasonicvibrations to the material being processed have not been successful,since hardening the vibration transmitting material would substantiallydiminish its vibration transmitting capabilities. In addition, hard orbrittle materials would rupture, crack or break when driven withsufficient energy to ultrasonically weld a work piece.

It is accordingly another specific object of the present invention toovercome the problems associated with wear of an ultrasonic welding tip.

Still another object of the present invention is to provide a wearresistant tip for an ultrasonic device which retain its vibrationtransmitting efficiency.

SUMMARY OF THE INVENTION

In carrying out the above and other objects in preferred embodiments, Iprovide a system for the production of polyester insulators that may beused in motor parts for hermetically sealed compressor applications. Oneform of insulator is used to separate end turns of different windingphases; and another form is used to cover winding connections. In theanother form, the insulators comprise generally tubular laminatedelectrical insulating sleeves having two wall areas which are, forexample, three layers thick. The insulator includes a section alongwhich a continuous weld seam is formed. In one three layer area, amaterial such as DuPont's Nomex polyamide insulating material issandwiched between two sheets or layers of a polyester material such asDu Pont's Mylar polyester material. An exemplary three layered insulatormay comprise one sheet of Mylar material and one sheet of Nomexmaterial, but formed about a cylindrical rod so that the Mylar sheet iswrapped upon itself and overlapped so that a polyester to polyester topolyester ultrasonic bond may be established and thus also form a threelayer area.

In the above mentioned one form, the insulators may be used for "phase"or end turn insulation; and comprise at least one strip of relativelyflat insulation having at least one elongate narrow strip of polyestermaterial ultrasonically welded thereto. Preferably, two insulatingstrips are held together with two elongate narrow strips by continuouslywelded seams running generally in the direction of the elongate strips.Each flat sheet may be cut in a direction substantially perpendicular tothe longitudinal direction of the elongate strips so as to form two endturn insulating portions from each flat sheet. The substantiallycontinuous ultrasonically welded seam or polyester to polyester bond isachieved with an ultrasonic welding tip made of conventional cold rolledsteel but having the surface thereof hardened. Surprisingly, thisprovides a work piece engaging surface which is not plagued by problemsof wear and yet provides an ultrasonic welding tip having good vibrationtransmitting characteristics.

In preferred forms of the invention, the substantially continuousultrasonical welding is accomplished so that no unattached extremitiesof the elongate narrow strip exist.

BRIEF DESCRIPTION OF THE DRAWING

The aforementioned and other objects, features, and advantages of thepresent invention will become more apparent from the following detaileddescription thereof when considered in conjunction with the drawings.However the exemplifications set out herein illustrate the preferredembodiments of the invention in one form thereof, and suchexemplifications are not to be construed as limiting in any manner.

FIG. 1 is a side view of a winding connection insulator embodying thepresent invention in one form;

Fig. 2 is an end view of the insulator of FIG. 1 after forming and priorto ultrasonic welding;

FIG. 3 illustrates the ultrasonic welding or bonding of a continuousseam on the insulator of FIG. 1;

FIG. 4 is an end view like FIG. 2 but after the welding process has beenperformed;

FIG. 5 illustrates an overall method of forming the insulator of FIG. 1;

FIG. 6 is a perspective view of a fabricated phase insulator embodyingthe invention in another form;

FIG. 7 is a sectional view along the line 7--7 of the insulator of FIG.6 illustrating the fused bond thereof;

FIG. 8 illustrates a method of fabricating the insulator of FIG. 6;

FIG. 9 illustrates the continuous ultrasonic welding step of FIG. 8;

FIG. 10 is an end view of the ultrasonic welding tip shown in FIG. 9;

FIG. 11 is a view, with parts removed and parts broken away, thatillustrate the interrelationships of a phase insulator and a connectioninsulator of my U.S. Pat. No. 3,748,510; and

FIG. 12 is a view in perspective, partially broken away to show detail,of a portion of a stator assembly after it has been fabricated, with theconnection insulator from my U.S. Pat. No. 3,748,510 installed andwinding end turns compacted and tied and with phase insulatorstherebetween.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The structure of the insulator 11 of FIGS. 1 through 5 is most easilyunderstood beginning with FIG. 2 which shows an end view of thatinsulator 11 after it is formed but before being ultrasonically welded.The insulator comprises a strip 13 of polyester material (e.g., Mylar)which is wrapped about itself into a cylindrical form and of a diameterso as to complete slightly more than two complete revolutions. Thisallows the two edges of the strip 13 to overlap for subsequent welding.Before forming the strip in this manner a second strip 15 of adissimilar material such as the Nomex material is superimposed on thestrip 13 so that in the forming process the Mylar makes at least onecomplete revolution about a former so as to prevent the strip 15 fromcoming into contact with the former. The Mylar and Nomex (both of whichnames are registered trademarks of E. I. du Pont de Nemours and Company)strips are continuously fed to a former so as to continuously create atubular structure having a cross section like that illustrated in FIG.2. As is well known to persons of ordinary skill in the art, Nomex strip(or sheet) material is a high temperature-resistant nylon paper that isa polyamide material.

The former itself may comprise a cylindrical rod 17 as shown partiallyin cross section in FIG. 3. The width of the strip 13 is somewhatgreater than twice the girth of the cylindrical rod 17 so that the strip13 will wrap about the rod 17 somewhat more than twice, and the width ofthe strip 15 is somewhat less than the girth (or circumference) of rod17. The strip 15 is asymmetrically placed on the polyester strip 13 sothat material 13 is exposed along one side thereof, and such exposedside is started about the rod 17 so that the configuration of FIG. 2will result. The process of forming the continuously fed superimposedstrips 13 and 15 into the configuration illustrated in FIG. 2 isaccomplished by the former 19 of FIG. 5, and is not set out in furtherdetail here, since it is not necessary to an understanding of thepresent invention. Once the material is formed into the configurationshown in FIG. 2, that portion of its periphery having three adjacentlayers of strip 13 is passed under the welding head 21 of FIG. 5. As thelaminated tube 11 passes under welding head 21, it is still wrappedabout the cylindrical rod 17 which functions to support the materialunder the welding head 21. The rod 17 may be supported within the former19 in cantilever fashion and may be counterbalanced for example, so toforce the polyester material upwardly toward the welding head 21.Alternatively, the rod 17 may be fixed in cantilever fashion and thewelding head 21 biased toward rod 17 so as to exert pressure on thethree layers of strip 13 between the welding tip and rod 17. The weldinghead itself is seen in greater detail in FIG. 3 and may comprise avibration transmitting portion or shank 23; and a tip 25. These twoportions are rigidly connected, in a mechanical sense, and may be formedas integral members or the tip 25 may be formed as a separatereplaceable portion. The tip 25 is caused to vibrate at an ultrasonicrate by standard ultrasonic welding techniques.

For example, the welding device may have a power supply for providingelectrical energy, means for converting the electrical energy intomechanical energy, and means for transferring the mechanical energy byway of the vibration transmitting portion 23 to the tip 25. The tip 25is continuously ultrasonically energized and the sheets 13 and 15 arecontinuously moved past the tip 25 so as to provide a continuous seam orbond between the three layers of polyester material 13. The ultrasonicvibrations cause motion between the polyester layers, thus inducingfrictional heat along their surfaces sufficient to fuse the materialstogether in the area of the weld without, however, heating the material13 to a point where thermal degradation takes place.

As noted earlier, the welding tips used in the ultrasonic welding ofpolyester materials experience excessive wear. I can now overcome thatproblem by making the tip 25 of cold rolled or cold drawn steel and thencase hardening at least the work engaging portion thereof. This casehardening (or other suitable surface hardening) of the welding tip doesnot substantially diminish its vibration transmitting characteristics,but does provide an extremely hard surface that is not readily worn awayas strip 13 is moved therepast.

As the material of tube 11 passes beyond the welding head 21 of FIG. 5,it has the configuration illustrated in FIG. 4, where dotted linesillustrate the weld regions between the three layers of material 13. Asseen in FIG. 4 the tube 11 is formed as a generally tubular, laminated,electrical insulating sleeve having two wall areas which are threelayers thick. However, it should be clear that the process of formingthese materials about the cylindrical rod 17 could for example, includeseveral more revolutions of the polyester material about the rod andcould include additional Nomex layers as well.

With reference again to FIG. 5, after welding, the tube continues to astation indicated generally as 27 where it is periodically severed so asto form the individual insulators 11. In one preferred embodiment,interpole and winding lead connection insulators for hermetically sealedrefrigeration units were manufactured in accordance with the presentinvention employing a cylindrical rod 17 having a one quarter inchdiameter. The Mylar-Nomex-Mylar insulating sleeves produced were about9/32 of an inch in diameter. The Mylar was about 0.003 to 0.005 inchesthick and 17/8 inches wide; while the Nomex was 0.003 inches thick and3/4 of an inch wide. Both materials were fed to station 19 from reels ofstrip material. The severing device 27 was actuated at a rate such as toproduce insulators 11 having an axial length of slightly over 2 inches.

Ladder-like insulators of the same general configuration as thatillustrated in perspective in FIG. 6 are employed in dynamoelectricmachine stators where the end portions 29 and 31 function to separatethe end turns of different winding phases. The connecting portions orsegments 33 and 35 pass along a pair of stator slots between the endfaces of the stator core. The width of the connecting portions 33 and 35must be such that they will fit within stator slots and the distancebetween the two end portions 29 and 31 should be slightly greater thanthe axial length of the stator in which the insulator of FIG. 6 is to beused. The distance between the end portions 29, 31 can be varied asrequired to satisfy the needs of stators of different axial lengths,while the connecting portions 33, 35 must be small enough to easilyenter stator slot openings.

Insulators as generally illustrated in FIG. 6 have been made heretoforeby relatively expensive processes. For example, an entire insulator hasbeen cut from a single wide strip of polyester material in which casethe window between end portions 29 and 31, and between the connectingportions 33 and 35 would represent a large and expensive piece of scrap.Of course, smaller scrap portions from the area outside the twoconnecting portions 33, 35 would also result.

Polyester material is relatively expensive, and discarding such a largepercentage of the material as scrap leads to relatively expensive endturn insulators. In an attempt to eliminate this costly scrap, twonarrow strips of polyester material have been provided with two endportions spot-welded thereto. However spot-welds often involve arelatively small welded mass of material and therefore tend to lackadequate strength and may break free during the stator assembly processresulting in a rejected stator. The new and improved end turn insulatorof FIG. 6 is now made possible by an economical and reliable processillustrated in FIG. 8, which process is somewhat analogous to theprocess presented by FIG. 5.

In FIG. 8, a plurality (such as two) of parallel elongated narrow flatstrips of polyester material 37 and 39 are continuously fed toward theright in FIG. 8 from a pair of reels of such material. Alternately,material may be fed from a single reel across means for splitting thesingle strip into the two strips 37 and 39.

A plurality of flat sheets 41 of polyester material are then disposedalong the parallel strips 37, 39 (for example, by feeding wide stripmaterial in a direction generally perpendicular to that of the narrowstrips and periodically severing such wide strip to deposit a flat sheet41 on the two narrow strips). The discrete pieces 41 and strips 37, 39pass under a pair of ultrasonic welding heads, each disposed inalignment with a path of a respective one of the strips, illustrated indotted lines as 43 and 45. These ultrasonic welding heads from acontinuous ultrasonic weld and secure or fasten the discrete pieces 41to the pair of narrow strips 37, 39; thus forming a ladder-like strip ofrelatively flat electrical insulators. These insulators may subsequentlybe cut or blanked out to the form or contour illustrated at 47.Thereafter, pieces 47 are severed along a line substantiallyperpendicular to the direction of travel of the strips 37 and 39, sothat a single discrete piece such as piece 41 ultimately forms one endportion 29 of one insulator and the other end portion 31 of anotherinsulator. As clearly revealed in FIG. 6, ultrasonic welding isaccomplished so that no unattached extremities of the legs or strips 33,35 exist. Thus, loose ends that may snag or catch on windings or on astator core are avoided. In addition, it will be noted from FIG. 6 thatthe legs 33, 35 and end pieces 29, 31 are welded together alongsubstantially the entire extent of the mutually overlapping oroverlapping portions thereof.

FIGS. 11 and 12 show the phase insulator of FIG. 6 as it is typicallyemployed in a stator assembly 110 of a dynamoelectric machine. The useof such insulator is well known to those skilled in the art, thereforeFIGS. 11 and 12 will not be explained in great detail. A connectioninsulator 121, of my U.S. Pat. No. 3,748,510, is shown only forillustration purposes, but it will be understood that tubular insulator11 of FIG. 1 could be used in a similar manner. Therefore, as eillustrated, the phase insulator will provide a layer of insulationbetween connections contained within insulator 121 and winding end turnportions 117, 118. Accordingly, with wall 138 of the insulator 121positioned against a face of phase insulator portions 31 and 31' adouble layer of positive insulation between winding end turn portions117, 118 adjacent thereto and connections will be provided. Phaseinsulator portion 29 is positioned between end turn portions ofdifferent winding phases at the opposite end of stator core 111 fromphase insulator portion 31. For completeness of description, it shouldbe noted that connection receiving portion 125 of insulator 121 includesa receptacle, open at 123, that receives a connection with external leadwire 124. Another external lead wire 128 is connected to winding leadwire 119. The connection 122 has been formed with a mechanical crimptype connection 120.

More specifically and as clearly taught by the schematic representationof FIG. 8, a piece 41 of electrical insulating material is positioned inoverlapped relationship across strips 37, 39 at Station A. Piece 41 maybe a pre-cut segment of insulating material or may be a portion of acontinuous length of insulating material that is fed into overlappingrelationship relative to the parallel strips 37, 39, and then severed tomake piece 41. At Station B ultrasonic welding heads 43, 45 weld therelatively overlapped or overlayed portions of piece 41 and strips 37,39 together. Welding heads 43, 45 are shown in dotted lines and it ispreferable to have them located adjacent to piece 41; therefore atStation A piece 41 is positioned above or below strips 37, 39, dependingon whether heads 43, 45 are above or below strips 37, 39. Portions ofpiece 41 are removed at Station C to give piece 47 a contouredconfiguration better illustrated by severed pieces 47 at Station D. Theultrasonic weld has attached extremities of strip 37, 39 to pieces 47 asillustrated at Station D. Piece 47 could be severed simultaneously withthe forming step accomplished at Station C, but it is preferred tocontour or form the shape (configuration) of piece 47 at Station C andsubsequently sever two adjacent pieces 47 (e.g., at another Station D)as clearly represented in FIG. 8.

The ultrasonic welding heads 43 and 45 join each flat sheet 41 to thestrips 37 and 39 along a substantially continuous seam running generallyin the direction of elongation of the strips 37 and 39. Welding head 45(it being noted that head 43 is the same as head 45) is betterillustrated in FIGS. 9 and 10.

FIG. 10 illustrates the welding head 45 looking in the direction ofelongation of the strips 37 and 39. Welding head 45 comprises avibration transmitting portion 47, and a tip portion 49. The tip portion49 has a work piece engaging surface 51 which, as illustrated in FIG. 9,cooperates with a support member 53. The support member and work pieceengaging surface 51 are biased toward one another in known fashion, withthe two superposed pieces of polyester material 39 and 41 therebetween.The vibration transmitting portion 47 transmits ultrasonic vibrations tothe work piece engaging surface 51. This in turn induces a weld alongthe interface of layers 39 and 41. At least the work piece engagingsurface 51 is surface hardened to prevent excessive wear due to thecontinuous nature of the weld. However, the vibration transmissioncharacteristics of the tip are not adversely affected. Moreover,cracking of hardened tip surfaces has not been experienced.

As seen in FIGS. 7 and 9, the ultrasonic welding process causes a slightdiminution in thickness of the joined materials. The typicalpolyethylene terephthalate insulating strips employed to make theinsulator of FIG. 6 were about 0.003 inches thick, but the resultingthickness of a typical weld region was only about 0.004 inches thick.However, this 0.002 inch loss of total two layer thickness does notimpair the insulating qualities of the resulting product.

The art of sonically or ultrasonically welding has previously beendeveloped and is represented, for example, by patents that are assignedto Branson Instruments, Incorporated, of Stamford, Conn. Some of theBranson owned patents, the disclosures of which are incorporated hereinby reference, are U.S. Pat. Nos. 3,224,916; 3,367,809; and 3,499,808. Aspreviously stated, common materials (e.g., cold drawn or cold rolledsteel) may be used for welding tips after it has been case hardened. Theexact degree of hardness of the tip is not critical, so for teachingpurposes only, it is noted that the tools herein shown had a surfacehardness of about 65, Rockwell C scale; and were case hardened to adepth of about 0.021 of a inch. These tools, when energized at 20,000hertz, did not crack and did not show evidence of wear when strips 37,39, and 41 (of FIG. 8) were 0.0075 of an inch thick Mylar; and whenstrip 13 (FIGS. 2 and 4) was made of different thicknesses (e.g., 0.003,0.005, and 0.010 of an inch thick) Mylar; even though the tips 21 and 49were continually energized during formation of insulators embodying theinvention as described above.

While the present invention has been described with respect to preferredembodiments thereof, numerous modifications will suggest themselves tothose of ordinary skill in the art. Accordingly the scope of the presentinvention is to be measured only by that of the appended claims.

What I claim as new and desire to secure by Letters Patent of the U.S.is:
 1. A method of assembling together at least a portion of one stripof electrically insulating material and at least one other segment ofelectrically insulating material to form electric motor insulators ofthe type having at least one first elongate insulation piece forplacement in an axially extending slot of a motor core, and havingspaced apart insulation pieces for placement between the end turnportions of different phase windings supported on the motor core withthe spaced apart insulation pieces interconnected by the at least onefirst elongate insulation piece, the method comprising the steps of:moving the strip in a longitudinal direction; overlapping a firstportion of the strip and the other segment of insulating material;welding together the overlapped segment and first portion of the stripwhile they are disposed between a support and an energized welding tool;and subsequently severing the strip material along a line transverse tothe longitudinal extent thereof so as to form a discrete insulatorhaving at least one elongated insulation piece that can be accommodatedin a core slot, and spaced apart insulation pieces connected together bythe at least one first elongate insulation piece that can each bedisposed between end turn portions of at least two different windings.2. A mechanical manufacturing method of fabricating an electricalinsulator by assembling electrical insulator portions, the methodcomprising: moving at least two overlapped portions of an electricalinsulating material adjacent to an ultrasonic welding device; andsecuring at least one other portion of electrical insulating material tothe at least two portions while the overlapped portions are adjacent tothe ultrasonic welding device, and thereafter contouring and cuttingindividual electrical insulator segments out of at least one of theportions after the ultrasonic weld has been formed.
 3. A method offorming insulators from electrically insulative strip material and atleast one other electrically insulating material comprising: moving thestrip material and the other electrically insulating material about acylindrical former having its axis in generally the same direction asthe motion of the materials; forming a multiple layer sleeve having aninner and outer wall of the strip material; enclosing the otherelectrically insulating material within the inner and outer walls; andsecuring the sleeve with an ultrasonic weld along a seam formed by onlythe strip material.
 4. A method of forming insulators from at least onereeled supply of longitudinally extending electrically insulatingmaterial and at least one other piece of electrically insulatingmaterial comprising the steps of: unreeling a first longitudinallyextending portion of insulating material and moving it in a longitudinaldirection; relatively overlapping a first portion of the firstlongitudinally extending portion of insulating material and the at leastone other piece of insulating material; ultrasonically welding the firstlongitudinally extending portion of insulating material and the at leastone other piece while the first longitudinally extending portion and atleast one other piece are adjacent to an energized ultrasonic weldingtool; and severing the first longitudinally extending portion ofinsulating material along the longitudinal extent thereof so as to forma discrete insulator comprising at least the at least one other piece ofinsulating material and the first longitudinally extending portion ofinsulating material.
 5. The method of claim 4 wherein a support isprovided comprising a rod supported in cantilever fashion with acylindrical surface thereof lying adjacent to the ultrasonic weldingtool, the reeled supply of material is in flat strip form, and themethod further comprises: providing a second reeled flat strip ofinsulating material; superimposing the first and second strips; andforming the superimposed strips about the rod.
 6. The method of claim 5wherein the rod is cylindrical and the width of the first reeled stripis somewhat greater than twice the circumference of the rod; and thewidth of the second strip of material is somewhat less than thecircumference of the cylindrical rod; the step of superimposing furthercomprising the step of asymmetrically placing the second strip on thefirst strip so that material of the first strip is exposed along oneside thereof; and the step of forming further comprises the step offorming a tubular insulator structure with the material of the secondstrip sandwiched between spaced apart layers of material of the firststrip.
 7. The method of claim 6 wherein the material of the second stripis not overlapped on itself and a welded seam is formed only alonginterfaces between overlapping portions of the first strip of material.8. The method of claim 4 wherein the at least one other piece ofelectrically insulating material comprises a piece of material orientedtransversely from the longitudinally extending portion of material. 9.The method of claim 4 wherein at least two longitudinally extendingportions of electrically insulating material are moved in a longitudinaldirection; a plurality of other pieces of insulating material are placedtransversely relative to the two longitudinally extending portions ofmaterial; and wherein the step of severing comprises severing bothlongitudinally extending portions along the longitudinal extent thereof.10. The method of claim 9 wherein one of the pieces of insulatingmaterial is severed each time that the strips are severed.
 11. Themethod of claim 9 wherein the longitudinally extending portion andpieces are polyester material.
 12. The method of claim 4 wherein theultrasonic welding tool is formed of common steel, and is provided witha hardened surface.
 13. A mechanical manufacturing method offabricating, by assembling, ladder-like insulators from a plurality ofseparate insulation pieces, the insulators comprising insulation for anelectric motor having a slotted magnetic core, first and second phasewindings having portions disposed in slots of the core and end turnportions adjacent the core end faces and wherein at least one firstelongate insulation piece extends along one of the core slots, andspaced apart insulation pieces connected together by at least one firstelongate insulation piece disposed between end turn portions of thefirst and second phase windings, the method including assembling theladder-like insulator from at least one first segment of electricallyinsulating material and at least one other segment of electricallyinsulating material and comprising the steps of: moving the at least onefirst segment in a longitudinal direction; arranging a first portion ofthe at least one first segment and the at least one other segment ofinsulating material in mutually overlapping relationship relative to oneanother; welding the overlapped portions of the at least one othersegment and first portion of the at least one first segment togetherwhile they are located between a support and an energized welding tool;and forming a contoured configuration to the ladder-like insulator. 14.A mechanical maufacturing method of fabricating by assembling, for anelectric motor, insulators from at least one reeled piece ofelectrically insulating material and at least one other piece ofelectrically insulating material comprising the steps of: unreeling thepiece of insulating material and moving it in a longitudinal direction;arranging a first portion of the piece with the at least one other pieceof insulating material so that parts thereof are in overlapping relationand welding the overlapped parts of the first portion of the piece andthe at least one other piece while they are located between a supportand an energized welding tool to form a weld and thus form a ladder-likestructure; and establishing a desired form of a portion of theladder-like structure after the weld has been formed.